RESUMO
Inorganic lead halide perovskite quantum dots (CsPbX3 QDs (X = Cl, Br, or I)) have attracted more and more attention due to their high absorption coefficient, narrow emission band, high quantum efficiency, and tunable emission wavelength. However, CsPbX3 QDs are decomposed when exposed to bright light, heat, moisture, etc., which leads to severe luminous attenuation and limits their commercial application. In this paper, CsPbBr3@glass materials were successfully synthesized by a one-step self-crystallization method, including melting, quenching and heat treatment processes. The stability of CsPbBr3 QDs was improved by embedding CsPbBr3 QDs into zinc-borosilicate glass. Then, the CsPbBr3@glass was combined with polyurethane (PU) to form a flexible composite luminescent film CsPbBr3@glass@PU. This strategy enables the transformation of rigid perovskite quantum dot glass into flexible luminescent film materials and further improves the photoluminescence quantum yield (PLQY) from 50.5% to 70.2%. The flexible film has good tensile properties, and its length can be strained 5 times as long as the original length. Finally, a white LED was encapsulated by combining CsPbBr3@glass@PU film and red phosphor K2SiF6:Mn4+ with a blue LED chip. The good performance of the obtained CsPbBr3@glass@PU film indicates that it has potential application in flexible liquid crystal displays (LCDs) as a backlight source.
RESUMO
A series of Gd2-xMoO6:xEu3+ (x = 0.18-0.38) nanophosphors were synthesized by the solvothermal method. The properties of these nanophosphors were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), fluorescence spectroscopy and diffuse reflectance spectroscopy. Gd2-xMoO6:xEu3+ nanophosphors have a strong excitation band in the NUV region and emit red light with high color purity by efficient energy transfer from the MoO66- group to Eu3+ ions. Red LEDs and WLEDs were fabricated using a 370 nm chip and Gd2-xMoO6:0.26Eu3+ nanophosphors, which showed good electroluminescence performance. At a driving current of 20 mA, WLEDs displayed CIE coordinates of (0.3297, 0.3869), a correlated color temperature (CCT) of 5604 K and a high color rendering index (Ra) of 91.6. This work demonstrates that Gd2-xMoO6:xEu3+ phosphors are promising red phosphors excited by a NUV chip for WLEDs.